In a case of a hydraulic brake, when a brake pedal is operated, braking hydraulic pressure is applied from a master cylinder, so that braking of a vehicle is performed.
In this case, when braking force larger than static friction force between a road and a tire is applied to the tire, a slip phenomenon, that is, a phenomenon in which the tire slips on the road, is generated. In order to prevent the slip phenomenon and secure stable braking force, an anti-lock brake system (ABS) was developed, and the ABS may detect a slip phenomenon, adjust braking hydraulic pressure according to the detection, and enable a vehicle to stop with the shortest distance.
The ABS may include an electronic control unit (ECU) for controlling electric elements, a plurality of solenoid valves for controlling braking hydraulic pressure transferred to each hydraulic brake, an accumulator, and a hydraulic control device, such as a hydraulic pump. In common, a slip valve is calculated based on a wheel speed detected by a sensor and a speed of a vehicle body estimated from the wheel speed, and when the calculated slip value reaches a predetermined slip valve, the ABS operates.
In relation to this, a method of controlling an ABS for a vehicle according to a related art includes: calculating the amount of slip of a vehicle, calculating the amount of threshold slip for operating an ABS, determining whether the amount of slip is larger than the amount of threshold slip, and controlling the ABS to operate when the case where it is determined that the amount of slip is larger than the amount of threshold slip is continuously generated by the predetermined number of times or more.
However, the related art controls the operation of the ABS only based on the amount of slip, so that the related art has a problem in that the related art cannot determine whether to brake considering a driving state, such as a case where a vehicle travels at a high speed or driving is performed in a circuit.